scholarly journals Infrared finiteness of a complete theory of charged scalars and fermions at finite temperature

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Pritam Sen ◽  
D. Indumathi ◽  
Debajyoti Choudhury
Keyword(s):  
Finite Temperature ◽  
Thermal Field ◽  
Heat Bath ◽  
Specific Form ◽  
Field Theories ◽  
Real Photon ◽  
Scalar Interaction ◽  
Zero Temperature ◽  
Neutral Fermion ◽  
Photon Interactions

AbstractIt is known that the infrared (IR) divergences accruing from pure fermion–photon interactions at finite temperature cancel to all orders in perturbation theory. The corresponding infrared finiteness of scalar thermal QED has also been established recently. Here, we study the IR behaviour, at finite temperature, of theories where charged scalars and fermions interact with neutrals that could potentially be dark matter candidates. Such thermal field theories contain both linear and sub-leading logarithmic divergences. We prove that the theory is IR-finite to all orders in perturbation, with the divergences cancelling order by order between virtual and real photon corrections, when both absorption and emission of photons from and into the heat bath are taken into account. The calculation follows closely the technique used by Grammer and Yennie for zero temperature field theory. The result is generic and applicable to a variety of models, independent of the specific form of the neutral-fermion–scalar interaction vertex.

SCHWINGER α-PARAMETRIC REPRESENTATION OF FINITE TEMPERATURE FIELD THEORIES: RENORMALIZATION

1990 ◽  
Vol 05 (23) ◽  
pp. 4427-4440 ◽  
Author(s):  
M. BENHAMOU ◽  
A. KASSOU-OU-ALI
Keyword(s):  
Temperature Field ◽  
Scalar Field ◽  
Finite Temperature ◽  
Short Range ◽  
Parametric Representation ◽  
Field Theories ◽  
Compact Form ◽  
Zero Temperature ◽  
Feynman Amplitudes ◽  
Temperature Scalar

We present the extension of the zero temperature Schwinger α-representation to the finite temperature scalar field theories. We give, in a compact form, the α-integrand of Feynman amplitudes of these theories. Using this representation, we analyze short-range divergences, and recover in a simple way the known result that the counterterms are temperature-independent.

ANOMALIES AT FINITE TEMPERATURE AND DENSITY

1994 ◽  
Vol 09 (09) ◽  
pp. 1423-1442 ◽  
Author(s):  
A. GÓMEZ NICOLA ◽  
R. F. ALVAREZ-ESTRADA
Keyword(s):  
Analytic Continuation ◽  
Finite Temperature ◽  
Arbitrary Number ◽  
Field Theories ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Zero Temperature ◽  
Functional Methods ◽  
Abelian Case ◽  
The One

Chiral anomalies for Abelian and non-Abelian quantum field theories at finite temperature and density (FTFD) are analyzed in detail in both imaginary and real time (IT and RT) formalisms. IT and RT triangle diagrams and IT functional methods (à la Fujikawa) are used at FTFD. The vector anomaly (the one regarding the lepton and baryon numbers) in the Weinberg–Salam theory, for an arbitrary number of fermion families, is also treated using IT functional methods at FTFD. In all cases, the expressions for the FTFD anomalies (as functions of the corresponding quantities) turn out to be identical to those at zero temperature and density, thereby extending previous results by various authors for the finite temperature and zero density case. Moreover, the independence of anomalies from temperature and density is shown to be consistent, at least in the Abelian case, with the analytic continuation from the IT formulation to the RT one.

THE SCHWINGER α-PARAMETRIC REPRESENTATION OF THE FINITE-TEMPERATURE FIELD THEORY: RENORMALIZATION II

1992 ◽  
Vol 07 (01) ◽  
pp. 193-200
Author(s):  
MABROUK BENHAMOU ◽  
AHMED KASSOU-OU-ALI
Keyword(s):  
Field Theory ◽  
Temperature Field ◽  
Theta Function ◽  
Finite Temperature ◽  
Parametric Representation ◽  
Field Theories ◽  
Zero Temperature ◽  
Scalar Theory ◽  
Charged Scalar ◽  
Finite Temperature Field Theory

We extend to finite-temperature field theories, involving charged scalar or nonvanishing spin particles, the α parametrization of field theories at zero temperature. This completes a previous work concerning the scalar theory. As there, a function θ, which contains all temperature dependence, appears in the α integrand. The function θ is an extension of the usual theta function. The implications of the α parametrization for the renormalization problem are discussed.

Review of the holographic Lifshitz theory

2014 ◽  
Vol 29 (24) ◽  
pp. 1430049 ◽  
Author(s):  
Chanyong Park
Keyword(s):  
Field Theory ◽  
Finite Temperature ◽  
Quasinormal Mode ◽  
Thermodynamic Quantities ◽  
Black Brane ◽  
Zero Temperature ◽  
Hydrodynamic Properties ◽  
Relativistic Field ◽  
Thermal Entropy ◽  
Lifshitz Theory

We review interesting results achieved in recent studies on the holographic Lifshitz field theory. The holographic Lifshitz field theory at finite temperature is described by a Lifshitz black brane geometry. The holographic renormalization together with the regularity of the background metric allows to reproduce thermodynamic quantities of the dual Lifshitz field theory where the Bekenstein–Hawking entropy appears as the renormalized thermal entropy. All results satisfy the desired black brane thermodynamics. In addition, hydrodynamic properties are further reviewed in which the holographic retarded Green functions of the current and momentum operators are studied. In a nonrelativistic Lifshitz field theory, intriguingly, there exists a massive quasinormal mode at finite temperature whose effective mass is linearly proportional to temperature. Even at zero temperature and in the nonzero momentum limit, a quasinormal mode still remains unlike the dual relativistic field theory. Finally, we account for how adding impurity modifies the electric property of the nonrelativistic Lifshitz theory.

THE SPECIFIC HEAT OF A FERMI GAS AT LOW TEMPERATURE: A CLOSER LOOK AT THE lnT BEHAVIOR

1999 ◽  
Vol 13 (28) ◽  
pp. 3357-3367 ◽  
Author(s):  
A. REBEI ◽  
W. N. G. HITCHON
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Finite Temperature ◽  
Thermodynamic Potential ◽  
Fermi Gas ◽  
Zero Temperature

At finite temperature, a Fermi gas can have states that simultaneously hold a particle and a hole with a finite probability. This gives rise to a new set of diagrams that are absent at zero temperature. The so called "anomalous" diagram is just one of the new diagrams. We have already studied the contribution of these new diagrams to the thermodynamic potential (Phys. Lett.A224, 127 (1996)). Here we continue that work and calculate their effect on the specific heat. We will also calculate the finite temperature contribution of the ring diagrams. We conclude that the ln T behavior of the specific heat due to exchange gets canceled by the new contribution of the new diagrams, and that screening is not essential to resolve this anomaly.

scholarly journals DIFFERENTIAL RENORMALIZATION FOR CURVED SPACE AND FINITE TEMPERATURE

1995 ◽  
Vol 10 (19) ◽  
pp. 2819-2839 ◽  
Author(s):  
JORDI COMELLAS ◽  
PETER E. HAAGENSEN ◽  
JOSÉ I. LATORRE
Keyword(s):  
Finite Temperature ◽  
Field Theories ◽  
Coordinate Space ◽  
Renormalization Procedure ◽  
Central Idea ◽  
Curved Space ◽  
Diffeomorphism Invariance ◽  
Differential Renormalization ◽  
Specific Calculations ◽  
Scalar Theories

We derive, based only on simple principles of renormalization in coordinate space, closed renormalized amplitudes and renormalization group constants at one- and two-loop orders for scalar field theories in general backgrounds. This is achieved through a renormalization procedure we develop exploiting the central idea behind differential renormalization, which needs as the only inputs the propagator and the appropriate Laplacian for the backgrounds in question. We work out this coordinate space renormalization in some detail, and subsequently back it up with specific calculations for scalar theories both on curved backgrounds, manifestly preserving diffeomorphism invariance, and at finite temperature.

scholarly journals The pion quasiparticle in the low-temperature phase of QCD

2018 ◽  
Vol 175 ◽  
pp. 07045
Author(s):  
Bastian B. Brandt ◽  
Anthony Francis ◽  
Harvey B. Meyer ◽  
Daniel Robaina ◽  
Kai Zapp
Keyword(s):  
Low Temperature ◽  
Finite Temperature ◽  
Quark Mass ◽  
Pion Mass ◽  
Effective Theory ◽  
Temperature Phase ◽  
Zero Temperature ◽  
Low Temperature Phase

We extend our previous studies [PhysRevD.90.054509, PhysRevD.92.094510] of the pion quasiparticle in the low-temperature phase of two-flavor QCD with support from chiral effective theory. This includes the analysis performed on a finite temperature ensemble of size 20 × 643 at T ≈ 151MeV and a lighter zero-temperature pion mass mπ ≈ 185 MeV. Furthermore, we investigate the Gell-Mann–Oakes-Renner relation at finite temperature and the Dey-Eletsky-Ioffe mixing theorem at finite quark mass.

scholarly journals RKKY Interaction in Graphene at Finite Temperature

2019 ◽  
Author(s):  
Eugene Kogan
Keyword(s):  
Finite Temperature ◽  
Thermodynamic Potential ◽  
Real Space ◽  
Magnetic Impurities ◽  
Zero Temperature ◽  
Rkky Interaction ◽  
Imaginary Time ◽  
Direct Evaluation ◽  
Time Representation ◽  
Short Notice

In our publication from 8 years ago1 we calculated RKKY interaction between two magnetic impurities in graphene. The consideration was based on the perturbation theory for the thermodynamic potential in the imaginary time representation and direct evaluation of real space spin susceptibility. Only the case of zero temperature was considered. We show in this short notice that the approach can be easily generalized to the case of finite temperature.

QUANTUM MAGNETIC VORTICES AT FINITE TEMPERATURE IN (3 + 1)-D

2000 ◽  
Vol 15 (11n12) ◽  
pp. 731-735
Author(s):  
E. C. MARINO ◽  
D. G. G. SASAKI
Keyword(s):  
Correlation Function ◽  
Correlation Functions ◽  
Large Distance ◽  
Finite Temperature ◽  
Higgs Model ◽  
Magnetic Vortex ◽  
Zero Temperature ◽  
Magnetic Vortices ◽  
Vortex Lines ◽  
Distance Behavior

We study the effect of a finite temperature on the correlation function of quantum magnetic vortex lines in the framework of the (3 + 1)-dimensional Abelian Higgs model. The vortex energy is inferred from the large distance behavior of these correlation functions. For large straight vortices of length L, we obtain that the energy is proportional to TL2 differently from the zero temperature result which is proportional to L. The case of closed strings is also analyzed. For T = 0, we evaluate the correlation function and energy of a large ring. Finite closed vortices do not exist as genuine excitations for any temperature.

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